Imperial College London
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DrSteffenBerg

Faculty of Engineering, Department of Earth Science & Engineering

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Contact

 

steffen.berg Website

 
 
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Location

 

1M10cACE ExtensionSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Berg:2017:10.1007/s11242-017-0830-3,
author = {Berg, S and van, Wunnik J},
doi = {10.1007/s11242-017-0830-3},
journal = {Transport in Porous Media},
pages = {229--246},
title = {Shear rate determination from pore-scale flow fields},
url = {http://dx.doi.org/10.1007/s11242-017-0830-3},
volume = {117},
year = {2017}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Aqueous solutions with polymer additives often used to improve the macroscopic sweep efficiency in oil recovery typically exhibit non-Newtonian rheology. In order to predict the Darcy-scale effective viscosity   eff required for practical applications often, semi-empirical correlations such as the Cannella or Blake–Kozeny correlation are employed. These correlations employ an empirical constant (“C-factor”) that varies over three orders of magnitude with explicit dependency on porosity, permeability, fluid rheology and other parameters. The exact reasons for this dependency are not very well understood. The semi-empirical correlations are derived under the assumption that the porous media can be approximated by a capillary bundle for which exact analytical solutions exist. The effective viscosity   eff(  Darcy) as a function of flow velocity is then approximated by a cross-sectional average of the local flow field resulting in a linear relationship between shear rate    and flow velocity. Only with such a linear relationship, the effective viscosity can be expressed as a function of an average flow rate instead of an average shear rate. The local flow field, however, does in general not exhibit such a linear relationship. Particularly for capillary tubes, the velocity is maximum at the center, while the shear rate is maximum at the tube wall indicating that shear rate and flow velocity are rather anti-correlated. The local flow field for a sphere pack is somewhat more compatible with a linear relationship. However, as hydrodynamic flow simulations (using Newtonian fluids for simplicity) performed directly on pore-scale resolved digital images suggest, flow fields for sandstone rock fall between the two limiting cases of capillary tubes and sphere packs and do in general not exhibit a linear relationship between shear rate and flow velocity. This indicates that some of the shortcomings of the semi-empirical correlations originate from the approximat
AU  - Berg,S
AU  - van,Wunnik J
DO  - 10.1007/s11242-017-0830-3
EP  - 246
PY  - 2017///
SN  - 0169-3913
SP  - 229
TI  - Shear rate determination from pore-scale flow fields
T2  - Transport in Porous Media
UR  - http://dx.doi.org/10.1007/s11242-017-0830-3
UR  - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000398088300004&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR  - http://hdl.handle.net/10044/1/64289
VL  - 117
ER  -
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